Venus sometimes swings very close to Earth, but then it heads to the far side of the Sun, a long way from us. Mercury never strays far from the Sun. Averaged over time, that makes Mercury Earth's nearest planetary neighbor. Even better, it is on average the closest planet to every one of the other seven.
A large share of Earth's water molecules formed in the interstellar cloud that existed before the Sun was even born, more than 4.6 billion years ago. You are literally drinking a cosmic fossil.
By day, the Martian sky looks butterscotch because of fine dust hanging in the air. But at dusk, those same grains scatter blue light forward, creating a bluish glow around the Sun. Rovers have photographed these blue sunsets: the exact reverse of what we see on Earth.